This is a request for a high performance light microscope equipped with bright and dark field, phase, interference contrast, polarization, and fluorescence optics, complemented by a high sensitivity video camera (image intensification and contrast enhancement capabilities) and a time lapse recorder. There is no comparable integrated system on the Berkeley campus (200 biologists) of the University of California, although numerous researchers have standard microscopes, a partial range of optics and, in some cases, low sensitivity video cameras. This integrated system will serve 6 major users from the Departments of Molecular Biology, Zoology, Botany, and Physiology-Anatomy, whose research concerns cellular and developmental biology. The equipment will facilitate: 1) the time lapse recording of living cells injected or surface-labeled with fluorescent materials. This will be a primary use of the equipment. For such recording, very low light levels are required to preclude photochemical damage to the cells and bleaching of the fluorochrome; 2) indirect immunofluorescent detection of the cytoskeleton of small cells, where images are very faint; 3) immunofluorescent work with cells where background autofluorescence is a problem and the most selective filter combinations are needed; and 4) phase contrast, interference contrast, and polarization analysis of cell shape an movement, and of spindle dynamics in permeabilized cells.